The present invention relates to a printing apparatus which allows two modes of printing, i.e., printing by means of type elements, and dot-matrix printing with a matrix of dots.
Generally, a printing operation by types (hereinafter referred to as "type-printing") provides superior print quality but is low in printing speed. On the other hand, a dot-matrix printing operation is high in printing speed but low in print quality.
In consideration of such circumstances, there have been provided printing apparatuses which are equipped with two printing units or assemblies for performing both type-printing and dot-matrix printing. In such printing apparatuses known in the art, however, the two printing assemblies are selectively moved, as required, into a printing position corresponding to a print line defined on a platen so that a printing is effected by the selected one of the two printing assemblies. Alternatively, the printing assembly at the printing station is changed from one to the other so that the printing is effected by the selected printing assembly. In such arrangements, a selective movement or change of the two printing assemblies for one printing position is extremely troublesome. Further, such printing arrangements of the prior art are incapable of selective printing operation in one of type-printing and dot-matrix printing modes or concurrent printing operations in these two modes at different positions on a sheet of paper.